title: A clinical and histological comparison of flashscanning versus pulsed technology in carbon dioxide laser facial skin resurfacing.
abstract: BACKGROUND
  Two different carbon dioxide (CO2) laser systems are currently in use for skin resurfacing. The vast majority of lasers use a pulsed beam, like the Coherent 5000C, but Sharplan uses scanning technology.
  
  
  OBJECTIVE
  We describe a clinical and histological comparison of these two laser technologies in order to determine if there are differences in the outcome.
  
  
  METHODS
  Twenty-two female patients underwent facial skin resurfacing using the Coherent 5000C UltraPulse CPG on one side of the face and the Sharplan Silk Touch on the contralateral side of the face. The clinical appearances were assessed periodically after treatment and punch biopsies were taken preoperatively and after 7, 21, and 90 days. Tissue was stained with Hematoxylin-Eosin, Masson Trichrom, and with the Verhoeff technique. Histological evaluation was performed on randomized samples taken from the same patient. Epidermis/dermis expression, collagen compaction, and elastin fiber quantity were compared to evaluate if any differences existed.
  
  
  RESULTS
  The side treated by Coherent healed more rapidly and with excellent cosmesis. Greater erythema was observed on the Sharplan side, but had disappeared at the 90-day evaluation. At this time the quality of the results was similar with no particular difference between the sides treated by the Coherent or the Sharplan lasers. At the histological level, although tissue recovered faster on the Coherent side at the 7-day control, at 90 days the collagen was better compacted and organized on the Sharplan side. Similarly, the quantity of the elastin was significantly more enhanced on the Sharplan side.
  
  
  CONCLUSIONS
  Irradiated laser energy density in relation to time, and the way that it is delivered, should play an important role at the moment of producing collagen shrinkage. The SilkTouch delivers laser energy more aggressively, thereby producing a more intense inflammatory tissue reaction, which results in slower recovery of tissue, compared with the Coherent CPG. More active enhancement of vascularization found in the Sharplan is likely to be the reason for a more effective collagen proliferation and compaction. These changes, together with the increase in elastin in the dermis, may produce longer lasting effects in skin resurfacing.
authors.affiliation: Instituto Médico Vilafortuny/Fundación Antoni de Gimbernat, Cambrils, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Trelles
authors.forename: J
authors.initials: J
authors.lastname: Rigau
authors.forename: T K
authors.initials: TK
authors.lastname: Mellor
authors.forename: L
authors.initials: L
authors.lastname: García
mesh_terms: D000328:Adult; D000368:Aged; D062109:Dermatologic Surgical Procedures; D005145:Face / Q000601:surgery*; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000295:instrumentation* / Q000379:methods; D008875:Middle Aged; D015361:Rhytidoplasty; D012867:Skin / Q000473:pathology; D015595:Skin Aging; D014945:Wound Healing